($55) EP -- Are large bets a sign of weakness or strength?

[Bazuul]

PartyPoker, Big Blind is t30 (9 handed) Converter on pregopoker.com

UTG (t1195)
Hero (t940)
MP1 (t1195)
MP2 (t1680)
MP3 (t930)
CO (t225)
Button (t960)
SB (t1930)
BB (t945)

Preflop: Hero is in UTG+1 with A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/spade.gif[/img]
<font color="red">UTG raises t120</font>, Hero calls t120, <font color="gray">MP1 folds</font>, <font color="gray">MP2 folds</font>, <font color="gray">MP3 folds</font>, <font color="gray">CO folds</font>, <font color="gray">Button folds</font>, <font color="gray">SB folds</font>, <font color="gray">BB folds</font>

Flop: (t285) 2[img]/images/graemlins/diamond.gif[/img] 4[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/club.gif[/img] (2 players)
<font color="red">UTG bets t250</font>, Hero ????

What is Hero's play, and what is UTG's range?